Answer:
152.7 cm/s
Step-by-step explanation:
The radius of DVD, r = 6 cm
The angular speed of DVD, ![\omega=243\ rev/min=25.45\ rad/s](https://tex.z-dn.net/?f=%5Comega%3D243%5C%20rev%2Fmin%3D25.45%5C%20rad%2Fs)
We need to find the linear speed of the DVD.
The relation between linear speed and angular speed is given by :
![v=r\omega\\\\v=0.06\times 25.45\\\\v=1.527\ m/s](https://tex.z-dn.net/?f=v%3Dr%5Comega%5C%5C%5C%5Cv%3D0.06%5Ctimes%2025.45%5C%5C%5C%5Cv%3D1.527%5C%20m%2Fs)
or
v = 152.7 cm/s
So, the linear speed of the DVD is 152.7 cm/s.
$2800
Please mark brainliest
![Volume\,\,of\,\,cone=1527.1\,\,cm^3](https://tex.z-dn.net/?f=Volume%5C%2C%5C%2Cof%5C%2C%5C%2Ccone%3D1527.1%5C%2C%5C%2Ccm%5E3)
So, Option C is correct.
Step-by-step explanation:
We need to find Volume of cone.
We are given:
π = 3.14
Length = 27 cm
Diameter = 15 cm
The formula used to find Volume of cone is:
![Volume\,\,of\,\,cone=\frac{1}{3}\pi r^2h](https://tex.z-dn.net/?f=Volume%5C%2C%5C%2Cof%5C%2C%5C%2Ccone%3D%5Cfrac%7B1%7D%7B3%7D%5Cpi%20%20r%5E2h)
We are given diameter but we need radius in the formula
So, Radius = Diameter/2 = 15/2 = 7.5 cm
We need to find height of cone.
Using Pythagoras theorem:
![h^2=p^2+b^2\\ (27)^2=p^2+(7.5)^2\\729=p^2+56.25\\p^2=729-56.25\\p^2=672.75\\Taking\,\,square\,\,root:\\p=25.93](https://tex.z-dn.net/?f=h%5E2%3Dp%5E2%2Bb%5E2%5C%5C%20%2827%29%5E2%3Dp%5E2%2B%287.5%29%5E2%5C%5C729%3Dp%5E2%2B56.25%5C%5Cp%5E2%3D729-56.25%5C%5Cp%5E2%3D672.75%5C%5CTaking%5C%2C%5C%2Csquare%5C%2C%5C%2Croot%3A%5C%5Cp%3D25.93)
So, Height of cone = p= 25.93
So, r= 7.5 and h= 25.93 and π = 3.14
Putting values in the formula:
![Volume\,\,of\,\,cone=\frac{1}{3}3.14*(7.5)^2*25.93](https://tex.z-dn.net/?f=Volume%5C%2C%5C%2Cof%5C%2C%5C%2Ccone%3D%5Cfrac%7B1%7D%7B3%7D3.14%2A%287.5%29%5E2%2A25.93)
![Volume\,\,of\,\,cone=1526.62](https://tex.z-dn.net/?f=Volume%5C%2C%5C%2Cof%5C%2C%5C%2Ccone%3D1526.62)
Rounding off to the nearest tenth:
![Volume\,\,of\,\,cone=1527.1\,\,cm^3](https://tex.z-dn.net/?f=Volume%5C%2C%5C%2Cof%5C%2C%5C%2Ccone%3D1527.1%5C%2C%5C%2Ccm%5E3)
So, Option C is correct.
Keywords: Volume of cone.
Learn more about Volume of cone at:
#learnwithBrainly
Rachel spends 6 hours 45 minutes a week trying to learn to play the violin.
Step-by-step explanation:
Step 1; Rachel learns for 45 minutes a day from Monday through Friday and in the weekend she learns to play the violin for one and a half hours. So she learns for the following periods of time
Monday - 45 minutes
Tuesday - 45 minutes
Wednesday - 45 minutes
Thursday - 45 minutes
Friday - 45 minutes
Saturday - 90 minutes (60 × 1.5 hours)
Sunday - 90 minutes (60 × 1.5 hours)
Step 2; To determine how much time she practices in a week we just add the individual times she plays on each day.
Total time practices in a week = 45 + 45 + 45 + 45 + 45 + 90 + 90 = 405 minutes = 6 hours 45 minutes.
Answer:
C) They are perpendicular lines.
Step-by-step explanation:
We first need to find the slope of the graph of the lines passing through these points using:
![m = \frac{y_2-y_1}{x_2-x_1}](https://tex.z-dn.net/?f=m%20%3D%20%20%5Cfrac%7By_2-y_1%7D%7Bx_2-x_1%7D%20)
The slope of the line that passes through (−12, 15) and (4, −5) is
![m_{1} = \frac{ - 5 - 15}{4 - - 12}](https://tex.z-dn.net/?f=%20m_%7B1%7D%20%3D%20%20%5Cfrac%7B%20-%205%20-%2015%7D%7B4%20-%20%20-%2012%7D%20)
![m_{1} = \frac{ - 20}{16} = - \frac{5}{4}](https://tex.z-dn.net/?f=m_%7B1%7D%20%3D%20%20%5Cfrac%7B%20-%2020%7D%7B16%7D%20%20%3D%20%20-%20%20%5Cfrac%7B5%7D%7B4%7D%20)
The slope of the line going through (−8, −9) and (16, 21) is
![m_{2} = \frac{21 - - 9}{16 - - 8}](https://tex.z-dn.net/?f=%20m_%7B2%7D%20%3D%20%20%5Cfrac%7B21%20-%20%20-%209%7D%7B16%20-%20%20-%208%7D%20)
![m_{2} = \frac{21 + 9}{16 + 8}](https://tex.z-dn.net/?f=%20m_%7B2%7D%20%3D%20%20%5Cfrac%7B21%20%20%2B%209%7D%7B16%20%20%2B%208%7D%20)
![m_{2} = \frac{30}{24} = \frac{5}{4}](https://tex.z-dn.net/?f=m_%7B2%7D%20%3D%20%20%5Cfrac%7B30%7D%7B24%7D%20%20%3D%20%20%5Cfrac%7B5%7D%7B4%7D%20)
The product of the two slopes is
![m_{1} \times m_{2} = - \frac{4}{5} \times \frac{5}{4} = - 1](https://tex.z-dn.net/?f=m_%7B1%7D%20%5Ctimes%20m_%7B2%7D%20%3D%20%20-%20%20%5Cfrac%7B4%7D%7B5%7D%20%20%5Ctimes%20%20%5Cfrac%7B5%7D%7B4%7D%20%20%3D%20%20-%201)
Since
![m_{1} \times m_{2} = - 1](https://tex.z-dn.net/?f=m_%7B1%7D%20%5Ctimes%20m_%7B2%7D%20%3D%20%20-%201)
the two lines are perpendicular.